Adrenaline-containing neurons in the medulla oblongata and hypothalamus have been implicated in playing a role in blood pressure regulation and hypothalamic regulatory processes. The finding by our group and others of higher levels of phenylethanolamine N-methyltransferase (PNMT) in the medullary C-1 and C-2 areas of spontaneously hypertensive rats (SHR) suggest that hyperactivity of epinephrine-synthesizing neurons may have a role in the development of maintenance of hypertension in this animal model